Internal-combustion turbine plant



Feb. 7, 1950 H. PFENNINGER 2,496,407

INTERNAL-COMBUSTION TURBINE PLANT- 2 Sheets-Sheet 1 Filed Aug. 7, 1945 Feb. 7, 1950 PFENNlNGER 2,496,407

INTERNAL-COMBUSTION TURBINE PLANT Filed Aug. 7, 1945 2 Sheets-Sheet 2 Patented Feb. 7, 1950 UNITED -'s'raxrrzs PATENT-OFFICE 2,496,497 m'rEaNAL-coMnUs'r'ron TURBINE rum-r Hans lienninger,

Baden, Switaerland, 'asslgnor to Aktiengesellschaft Brown, Boveri 8r Cie, Baden, Switzerland, a joint-stock company of Swltzen. r

land

Application August '1, 1945, SerlalNo. 609,427

In Switzerland August 24, 1944 8 Claims. (CI. 60-41) down to reduce the power required for the compressor, and this cooling results in a considerable loss of heat.

, Accordingto this invention, these ineflicient working conditions are avoided by operating the gas producer under approximately the same pressure as that of the combustion chamber of the turbine plant, and the air for operation of the gas producer is supplied at a somewhat higher pressure to overcome the pressure drop within the gas producer. a r

The known plants of this type bring the whole amount of compressed air tothe higher pressure and throttle down the airsupplied to the combustion chamber of the'gas turbine by an amount equal to the pressure drop in the gas producer. In these plants therefore the preponderant part ofthe compressed air. is throttled down to reduce its pressure, and this results in a considerable loss in power and efliciency.

The invention aims at avoiding these losses in that, as before, the whole amount of air is brought to the higher pressure, but the pressure drop of the operating air for the gas turbine is utilized to advantage. If for instance the plant has a preheater. for the main air supply, the fall in pressure in the preheater is made as great as that of the gas producer. If a number of blowers and turbines are connected in series, the air for the gas producer is taken off at those places where the pressure in the air circuit is higher than that at the combustion chamber bythe amount of the pressure drop in the gas producer. This condition however is not suflicient to give satisfactory operation under all loads and, as a further requirement for practical operation, the pressure at the tapping place must rise and fall with varying loads in the same sense as the pressure changes at the entrance to the combustion chamber.

Objects of the invention are to provide combusexchanger in. which it under pressure adequate for direct delivery to the combustion chamber, and in which the entire volume of air-is compressed to a value appropriate for delivery to the gas producers. An object is to provide combustion turbine plants of the type stated in which the energy input represented by the compression of the major portion of the air to a pressure above that of the combustion chamber is recovered, for example by employing the excess pressure to forcethe air through a heat absorbs energy. Another object is to provide a turbine plant which includes a plurality of air compressors and an air circuit with portions thereof under different pressures,

at least one gas producer for converting solidfuel to a gaseous state, and an air supply connection to the gas producer from a point in the air circuit at which the pressure is higher than and varies with the pressure at the entrance to the combustion chamber.

These and other objects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawings in which:

Fig. 1 is a schematic diagram of a single stage combustion turbine plant embodying the invention; Y Fig. 2 is a similar schematic diagram of a multiple stage turbine plant; and

Fig. 3 is a fragmentary schematic diagram of a modified arrangement for a multiple stage combustion turbine plant.

In a single stage internal combustion plant as shown in Fig. 1, the reference numeral I identifies a compressor for supplying air through a heat exchanger 2 to the combustion chamber 3 of the turbine 4 that drives the compressor l and a tion turbine plants that may be operated eiiigenerator 5. A motor 6 is provided for starting the turbine plant, the motor shaft being integral with or connected to the generator shaft.

The fuel for operating the turbine plant is coal or other gasifiable substances that are converted to gases in the gas producer 1 that operates under pressure established by connecting the air inlet line of the gas producer to a point 8 in the compressed air circuit at which the pressure is higher than that at the combustion chamber 3 by an amount equal to at least the pressure drop through the gas producer I. As shown, the tapping point 8 is located between the compressor 1 and the air inlet to the preheater 2, and the pres sure within the gas producer I therefore rises and falls automatically with the pressure in the main air circuit as determined by the load on the turbine plant.

.speedofthe Theregulation of the supply of combustion gas to the combustion chamber 3 is eii'ected by a throttle valve that may be located in the air inlet line to the gasproducer I or, as shown. in

the gas outlet line from the gas producer. The

control of the throttle valve 9 is eflected by any known or desired regulating system." As shown in Fig. 1, the setting of the regulating valve s'is controlled by the fluid pressure established atthe valve I by an oil pump it, the pressure varying with the adjustment of a bleed valve ll bya '1 governor II on a shaft driven by the turbine I. Since the fall in pressure'in the gas generator varies'with the depth of the charge layer and the formation 'of slag, the adjustment of throttle valve 9 is such that it is not fully open at normal load. In this way;

drop in the gas producer I can be compensated by opening the throttle valve 9 to maintain the,

production of gas for combustion at normal value. This normal adjustment of the throttle member gives the further advantage that in plants in which the load rises and falls with the number of revolutions, a load jolt can be absorbed more for combustion-isf-incr'eased at once by opening the throttle member 9, this action taking place before the change sults in the delivery of'a diil'erent volume of combustion air for the gas producer.

'It should also be' mentioned that apparatus according to the invention has the decided advantage overthe known types of regulation that the air supplied to the gas producer can be varied in the simplest way between zero and maximum without detriment to the pressor. The operation point 01' the, compressor is not aflected greatly by opening or closing the throttle member I, since the air not flowing to the gasproducer-l flows through the air preheater 2, and the amount oi combustion air dean increase in the pressure rapidlyfsince the production of gas in operating speed re-- efliciency ot the com-- output of compressor I the through a cooler II to the compressor I oi the high pressure stage,'and the remainder flows throughthegasproducerltothecombustion chamber 3. The mador'portion or the high presflows hrough heatexchangerlonitswaytothecmnbus tion chamberl'. The other portim oi the high pressure air from compressor I producer I where solid fuel is liverytothe combustion chamber 3'. gaseafrom the turbine 4' are the air" supply for the combustion chamber I, and the exhaust gases from turbine I are the heating medium valves 0. 0' are provided formulating the iiow of combustion gasu to the chambers 3, I, the

valves being regula ed by. speed governors i2,

livered to the 'gas producer is small in comparison with the total amount of air delivered.

Asalready mentioned, the advantage compressor-turbine assembly and v the arrangement gives that upon change in the rotary pressure changefin the combustion chamber connected with the same, the corresponding pressure change is automatically set up in the gas producer-"I. I

In multistage internal combustion turbine plants with that operate with .diflerent pressure, each combustion chamber has its own gas producer that operates under approximately the same pressure as that oi' the combustion chamber. The air for combustion for the diirerent gas producers is takenfrom points along the motive fluid circuit at which thepressure at the tapping place and at the combustion chamber varies with the turiall in presis obtained bine speed in such manner that the sure necessary for the gas producer at all loads. The regulation is accomplished by a throttle member in the branch line fore or after the gas roducer.

A two stage turbine plant of this type is shown in Fig. 2, the several elements or the low pressure stage being identified by the same reference either behumerals as the corresponding elementsof the Fig. 1 turbine plant, andthe elements oi the high pressure stage being identified by primed reference numerals. Each stage includes, in general,- the same mechanical assembly as previously described but the entire live load is carried by the high pressure stage, i. e., the low pressure a number of combustion chambers revolutions becoming bustion gas maybe tapped to In 'this way,

combustion tor the pressure and high pressm-e stages The throttle valves may be controlled directly by the governors or, as shown, may be controlled indirectly by a pressure oil throttle valve 0, or it may be imposed on the combustiongasesattheoutputaideoifliem producer, as shown-bytbe throttle valve 0'.

The gas producers can be charged with exhaustgasesfmmtheturbines,andthisarrangement has the advantage that a lowerim of the temperatin'eofcombustion is attained inthegas producers by the reduction of carbon dioxide tocarbonmonoxide. -Asahowninhg.3,ahigh pressm-elarrbiriel'oramultiplestageaaembly deliver exhaust gases to the gasproducerloifalower-prusurestagethrough 'a line I, the tappingbeingmade attheturbine In plants where the additional procur in the gas producer working at the highest ramsure cannot be attained by suitable tapping of the motive fluid circuit, it is to provide an additional blower stage for the air for as producer. This is done so-that onLthe compressor, one or more addicombustion ofthe heat exchanger 2. Throttle tional stages are provided that compress mainly only the air for combustion of the gas producer. If the capacity for regulation is smaller than in the aforementioned arrangements, a suflicient range of regulation can be obtained by suitable construction of the additional stages. For instance, if an axial flow compressor is used, where the production of pressure in the additional fan is small, a blower characteristic can be attained by a small vane angle that permits a throttling of the air for combustion of the gas producer from full load to no-load. As in the earlier arrangements, the air not required by the gas producer is sent directly to the combustion chamber.

It is to be understood that the invention is not limited to the particular arrangements herein shown and described, and that various modifications that may occur to those familiar with the design and construction of combustion turbine plants fall within the scope of my invention as set forth in the following claims.

I claim:

1. In a combustion turbine plant, the combination comprising coupled combustion gas turbine and air compressor units, a combustion chamber, a fuel gas producer, a conduit for combustion gas between said combustion chamber and turbine, a conduit for fuel gas between said gas producer and combustion chamber, means delivering a portion of the air from said compressor to said gas producer at a pressure higher than the operating pressure of said combustion chamber, an energy transfer apparatus such as a heat exchanger or auxiliary turbine, and means delivering the remainder of said air from said comprejssor to said combustion chamber through said energy transfer apparatus to effect a drop in air pressure therein approximating the drop in pressure in said gas producer.

2. In a combustion turbine plant, the invention as recited in claim 1 wherein said energy-transfer apparatus is a heat exchanger in which the heating medium is the exhaust gas from said turbine.

3. In a combustion turbine plant, the invention as recited in claim 1, in combination with means for regulating the relative quantities of air delivered from said compressor to said combustion chamber through said gas producer and said energy-transfer apparatus.

4. In a combustion turbine plant, the invention as recited in claim 1, in combination with means for regulating the relative quantities of air delivered from said compressor to said combustion chamber through said gas producer and said energy-transfer apparatus, said regulating means comprising a throttle valve in the air delivery means to said gas producer.

5. In a combustion turbine plant, the invention as recited in claim 1, in combination with means for regulating the relative quantities of air delivered from said compressor to said combustion chamber through said gas producer and said energy-transfer apparatus, said regulating means comprising a throttle valve in the fuel gas conduit from said gas producer.

6. In a combustion turbine plant, a plurality of turbine-compressor stages operating under different pressures, a combustion chamber for each stage, a gas producer for each stage for generating fuel gases from solid fuel, means for supplying combustion air to each gas producer under pressure suillcient for a flow of the fuel gases to the combustion chambers of the associated stages, and conduit means for supplying combustion air to the combustion chambers of the several stages, the compressor of a high pressure stage supplying combustion air to the combustion chamber of that stage and to the gas producer of that stage at a pressure in excess of the operating pressure of the associated combustion chamber, the conduit means for supplying combustion air to the combustion chamber of said high pressure stage being independent of the supply of combustion air to the gas producer of that stage and including energy-transfer means developing a pressure drop approximating the pressure drop of the gas producer of that stage whereby fuel gas and combustion air for that stage enter the combustion chamber at approximately equal pressures.

7. In a combustion turbine plant, the invention as recited in claim 6 wherein an exhaust gas connection from the turbine of a high pressure stage supplies combustion air to the combustion chamber of a lower pressure stage.

8. In a combustion turbine plant, the invention as recited in claim 6 wherein said energytransfer means comprises a heat exchanger having a heating medium inlet connected to the exhaust side Of a turbine of a lower pressure stage.

HANS PFEN'NINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,055,385 Noack Sept. 22, 1936 2,225,310 Lindhagen et al. Dec. 17, 1940 2,225,311 Lysholm Dec. 17, 1940 FOREIGN PATENTS Number Country Date 492,881 Great Britain Sept. 28, 198B 

